Clouded Yellows are migrants from the Continent. Just a handful of records are submitted in most years, but occasionally Clouded Yellows are seen in Scotland in large numbers, such as in 1877, 1947, 1983, 1992, 1998, 2000 and 2006. Most are seen along the coastline, but in good years they will spread long distances inland. There is evidence that, like other migrant butterflies, some butterflies attempt a return journey in the autumn.

Identification

Clouded Yellows could be confused with Brimstones, but are orange-yellow rather than lemon yellow, and have black patches on the wings.

Both Swallow-tailed and Brimstone moths are occasionally seen in the daytime and are sometimes mistaken for Clouded Yellows.

Life cycle & flight period

Clouded Yellows are most often seen in August, with the bulk of records coming between May and September. They may attempt to breed and if so, the caterpillars can develop quickly, often producing a locally bred adult generation if time allows, but none of the life stages can currently survive our winters.

Larval foodplant

The adults will lay eggs on a variety of plants, including clovers, vetches, bird’s-foot-trefoils and other leguminous plants.

Habitats

The most likely place that Clouded Yellows will be spotted is on coastal grasslands, but they can occur inland.